In general, a mobile communication system has been developed for the purpose of providing communications while securing user's mobility. With the rapid progress of technology, such a mobile communication system can now provide not only voice communications but also high-speed data communication services. Recently, as one of the next-generation of mobile communication systems, standardization of Long Term Evolution-Advanced (LTE-A) in 3GPP is currently underway. Setting a goal of standardization completion in the latter half of 2010, LTE-A has been developed as a technology to implement high-speed packet-based communication having a higher data rate than the data rate that is currently provided.
With the evolution of the 3GPP standard, a scheme to easily optimize a wireless network is under discussion in addition to a scheme to heighten the communication speed. In a mobile communication system, a cell having a small-sized service region has been frequently used to increase the capacity and to solve for the shaded region. Due to the small-sized service region, many problems, such as frequent handover failures, have occurred in supporting mobility. Nevertheless, application of system variables or development of an operating mechanism, that is suitable for the small-sized service region, has not been prepared in detail.